Erasmus Darwin and The Botanic Garden
The Lunar Society boasted several members of outstanding intellect, who quite cheerfully referred to themselves as lunaticks. Joseph Priestley was one, and another was Erasmus, the grandfather of Charles Darwin. Erasmus Darwin (1731–1802) believed that in the natural world species were constantly developing as they struggled to overcome the constraints imposed by their environment. He summarized his view of continual change in the following passage from his book Zoonomia, or, The Laws of Organic Life, published between 1794 and 1796.
Would it be too bold to imagine that, in the great length of time since the earth began to exist . . . that all warm-blooded animals have arisen from one living filament, which the great First Cause endued with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions and associations, and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down these improvements by generation to its posterity, world without end!
This picture of continual change is close to the theory advanced by Lamarck that by struggling against environmental constraints organisms modify their bodies and their offspring inherit those modifications. This leads to the emergence of new species, but in a progressive way driven by every organism's desire for self-improvement. Darwin did not develop it into a complete theory of evolution, and his ideas are very different from those of his grandson.
Erasmus Darwin was a physician, scientist, and inventor (he designed a rocket powered by hydrogen and oxygen, although it was never built), but during his lifetime he was best known as a poet. He was born, the youngest of seven children, on December 12, 1731, at Elston Hall, in Elston, Nottinghamshire. He was educated at Chesterfield Grammar School and St. John's College, University of Cambridge, and he studied medicine at Edinburgh Medical School. Having qualified as a physician, in 1756 Darwin settled in Nottingham and tried to establish a medical practice. This was not very successful, so in 1757 he moved to Lichfield, Staffordshire, where his success in saving the life of a patient who had been close to death made him popular and his practice prospered. Darwin married twice and had 14 or possibly 15 children, two or three of them illegitimate. After his second marriage he and his wife moved to Radbourne Hall near Derby and later into Derby itself. He died suddenly on April 18, 1802, soon after moving again, this time to Breadsall Priory, near Derby.
While he was in Lichfield, Darwin and several of his friends, one of whom was Samuel Johnson (1709–84), formed the Botanical Society of Lichfield, with the purpose of translating the works of Linnaeus from Latin into English. The task took seven years and ended with the publication of two books, A System of Vegetables in 1783 and 1795, and The Families of Plants in 1787. His careful study of Linnaeus inspired Darwin to write his two most famous poems. The first was The Loves of the Plants, which Darwin published anonymously in 1789. Its four cantos expounded the Linnaean system of classification, based on the reproductive structures of plants, and in it Darwin described female and male plants as though they were human brides and bridegrooms. A “botanic muse” guides the reader and between each of the cantos there is a dialog between the poet and the bookseller.
The Loves of the Plants proved instantly successful, and this encouraged Darwin to republish it, but this time adding another and more demanding poem, The Economy of Vegetation, in which Darwin celebrated scientific and industrial progress. Despite its title, much of it described mining, steel manufacture, and contemporary scientific theories. The two poems were published together in 1791, with The Economy of Vegetation preceding The Loves of the Plants, as The Botanic Garden. It was an immediate best seller.
The Botanic Garden was unique. No one had attempted to write a botanical text in heroic couplets, and no one has done so since. The poem describes 83 plant species, with extensive footnotes explaining the imagery. Darwin's stanza on the sundew (Drosera) gives a flavor of the work. Sundew is a carnivorous plant of peat bogs, where nutrients are scarce. Its leaves bear red-tipped hairs, each with a drop of a sticky substance that looks like dew—hence the name. An insect alighting on the plant to drink the dew is trapped. This is Darwin's description, in Canto I of The Loves of the Plants:
Queen of the marsh imperial Drosera treads
Rush-fringed banks, and moss-embroider'd beds
Redundant folds of glossy silk surround
Her slender waist, and trail upon the ground;
Five sister-nymphs collect with graceful ease,
Or spread the floating purple to the breeze;
And five fair youths with duteous love comply
With each soft mandate of her moving eye.
As with sweet grace her snowy neck she bows,
A zone of diamonds trembles round her brows;
Bright shines the silver halo, as she turns;
And, as she steps, the living lustre burns.
- Joseph Priestley and “Dephlogisticated Air”
- Stephen Hales, the Movement of Sap, and Transpiration
- Robert Hooke and the Cell
- Marcello Malpighi and the Microscopic Study of Plants
- Nehemiah Grew, Plant Reproduction, and Comparative Anatomy
- Nikolai Vavilov and the Origin of Cultivated Plants
- Gote Turesson and Plant Ecotypes
- Asa Gray and the Discontinuous Distribution of Plants